Question

Jennifer was going to sell all of her stamp collection to buy a video game. After selling half of them she changed her mind. She then bought fifteen more. How many did she start with if she now has 43?

Answer 1

Alright, we just need to reverse some operations done unto 43. Subtract the 15 from her collection.

43 - 15 = 28.


Sold half? Times half.
28 * 2 = 56

Make sure it works:

56 - 28 = 28. 28 + 15 = 43.

She had 56 cards to start with.